Hard metal compositions



Patented Aug. 19, 1952 s PATENT OFFICE HARD METAL CONIPOSITIONS JacobKurtz, Teaneck, N. J.

No Drawing. Application June 1, 1949,

' Serial No. 96,615

9 c aimsgjj (01. 75-136) This invention relates to hard metal compositions, especially to hard metal compositions suitable for hot pressingin combinationwith non metallic abrasive grains, such as diamond s,or

hard metallic'abrasive and cutting grains, and/or pieces, such ascemented hard carbides, having extensive adaptations in the mining andoil. well industries; It is an object of this invention to provide amaterial composition to be usedas matrix, that is hard, tough, abrasionresistant, easy to form, and press, that is easily welded to itself, andto.

vide a new composition of material particularlyadapted to be used incombination with inserted tungsten carbide tipsin rotary type rockdrilling bits; 'I-Ieretofore making diamond drill bits and the; like wasa long tedious process. The desired) quality of hardness and toughnessof the matrix material was diflicult to achieveandcontrol, and,

the crown containing the diamonds required an additional soldering orbrazing operation to bond it to the steel-shank. Frequently, due tomarked difierences inthe expansion coefllcients between;

the crown and the shank, the crowncrackedand broke; away from the shank,or strains would bet set: up in the structure to causethe crown to:break away shortly after it was put into service. Likewise when usingcemented carbide inserts,

the inserts would crack away from the main body of the material. Themain'body of the material would soon Wear away, or if made sufficientlyhard would crack in servicesho-rtly thereafter.

, Heretofore the hard cemented carbide inserts would have to be;brazed..into the holder as a" separateoperation, and due to the markeddifferences of expansion between the and ha r ide in e t t ma tr ns-w l.de-

carbide at the time of making the braze eliminates the aforementioneddiii'iculties. Briefly described; the hard alloy of the presentlnvention consists essentially of refractory metal carbides, tungstencarbide for example, cobalt, nickel, manganesecopper, and a small butefiective amount of beryllium combined in the proportions and accordingto the method described herebelowt' I first provide a refractorytungsten carbide,

200 mesh or finer made by anyknown means. Instead of tungsten carbide, Imay use any of the refractory, metal carbides, titanium, ZiI'COIli".

um, vanadium, chromium, tantalum and molybdenum or, suitablecombinations of carbides from this groupfor example a mixture of%tungsten carbide and 15% titanium carbideg A mixtureof 50% tungstencarbide, 35% molybdenum;

carbide, 15% titanium carbide. A mixture of 30% tungsten carbide, 30%molybdenum carbide, 20% vanadium carbide, 20% titanium carbide, etc. Itis to be understood that these groupings and combinations are only givenby way of example, and that this invention is by no means limitedthereto.

This finely divided metal carbide powder, or combinations of metalcarbide powders, is then placed a carbide lined or stainless steel ballmill, and to this is added 6% by weight of finely dividedpure cobaltmetal powder, and the two are ball milled together for asufiicientlylong time to uniformly distribute the cobalt throughout the -mass. Thisfirst ball milling will take from 6 to 96 hours depending of course onthe original fineness of the powders'used. It is essential however toget a uniform distribution and a thorough commingling of all theingredients. This I call refractory metal carbide mixture A.

I next, prepare a, bonding, densifying, and

hardening mixture, which I call mixture B. This mixture consists of purenickel, manganese, and copper powders, and beryllium in alloy form,

either as nickel-beryllium alloy, or beryllium cop-,,

taining 10% beryllium, so that the amount of beryllium in the alloymixture B is not less than 0.25% and not more than 3% by weight. The

presence of the small but efiective amount of beryllium provides analloy bonding material that can be heat treated to give a harder,tougher, and greater wear resistant body.

In preparing mixture B, I first weighout the requisite amount ofnickelpowder 200- mesh and I finer, and then add the required amount of thenickel beryllium alloy powder in finely divided form. The two arethoroughly mixed as by ball milling, until they are; thoroughlycommingled' and uniformly distributed. usually takes.

neonate from 1 to 4 hours. The manganese and the copper powder, bothpure and in finely divided form,

are then added in amounts specified below to bring the composition ofthis mixture to the re- All the powders are mixed and ball milled for afurther period to get a thorough distri ution of all the ingredients. 7y

The proportions constituting alloy mixture-B give a resultant alloycontaining 62.064.75% nickel 3.0-.25 Be 25.0% ;1vm

'The final alloy mixture is then formed by tnorcugmy in-ixingfroni90-50% of alloy mixture 'A a nd- 10-40% ofalloy mixture B.- Here againit is important to get a thorough mixing: te'aesur a uniformdistribution of all the ingrediiits; The final mixture I call mixture C.The fine may be donedry in carbide lined or stai ess'steei ball millsusing steel or carbide tans; er it may be mine wet us ngcarlbontetrachloride or the like. If the final ball milling is done wet,care must be exercised to continue the mixing while the.carbontetrachloride is driven un te-prevent segregation of any of theingredi ents. After thorough drying, mixture C can then be packed inairtight containers and is ready for use inmaking either (ii-aimsntiimpregnated core bits, or, in continuation with sintered hard metalcarbide-inserts, rotary t pe rock drilling bits, or in making any unitrequiring a hard, tough abrasi'oii resistant material.

- netntrtne allo'yof; this invention is to beused in making the diamondimpregnated corebits' 'oi' the rotary type rock drilling' bits, the;procedure'excerpt for modification of the carbon memes-end the mannerorholding the abrasive grain; and/or theiriserts in'plac'e, is the same.For the sake of simpli'city'I will describe a'method oi using the alloyof this inventionin'makinga diamond i'mpregnated core bit.

One form of apparatus as used in thehot-p'ress ing of thealloy of thisinvention, consists essentially ofhigh frequency furnace with'suitablecontrols-for temperature, and a hydraulic press witfilsuitaable controlsfor-pressure, having- (branch or graphite moulds suitably machined ti-receive and holdthediamon'ds or cementedhar'd carbide inserts in placetv 1 Thegraphite mould is-circular-in sectionand is suitably machined togive; an annular ree ssand any desired'bottom contour; In the bottom ofthis annular recess location'points or grooves are drill'e'd toreceivea'nd'hbldthe diamonds in place. In operation the steps areas-follows;The diamonds are carefully placed in the location grooves as'd'e'scrib'e'dabov'. A weighed amount of alloy powder mixture C is thencarefully-placed in annular space, and uniformly distributed. "A steelshank suitably machined, and having its' bott'om contour serrated,isthenplaced in the annular space on top of the alloy powder. The mouldassmbly is then placed in the high frequency furn'ace which ispositioned" on the bottom platen of a hydraulic press. Pressure isapplied on top face of the shank until a value approximately 500 poundsper square inch on the pressing area of the alloy powder being pressedis reached. The high frequency current is turned on, quickly heat ingmould to the requisite temperature where it is held for a period of timesufficient to allow complete densifica'tion and alloying of all theing'redients. Temperature and time will depend on the particularcomposition used and the size and weight of the piece being pressed.

A 2" outside diameter x 1% inside diameter ,x thick ring of the alloy ofthis invention was hot pressed and sintered and alloyed to a steel shankof the same outside and inside diameter dimensions in about 10 minutes.The high frequency furnace unit had a capacity of 30 kw.

, The initial cold pressure was approximately 500 pounds per squareinch. The maximum temperature was 1250 C. and final pressure at maximumsquare inch. As the temperature :begins to rise it w ill be noted thatthe pressure drops due to partial s'interingwhich' begins to take place.Pressure however is maintained fairly constant througho'utthis pressingoperation, and may even be increased to a higher value as the maximumtemperature is approached. maintained-on the assembly until the pressedand sintered assembly has cooled down to approximat'ely 800 C.

Therpre'ssure is then released and the assembly taken out of the furnaceand allowed to cool quickly to'approximate room temperature. The shankisthen removed from the mould. It will be found that the diamonds protrudethe predetermined amount, and are-securely imbedded in the alloymaterial and that the steel shank has beenthoroughly welded to the alloyforming a Bhave'a'sintering temperature of about 1100" 0.-

1200 C-. I Temperatures and pressures should be controlled within thelimits specified to obtain an alloy of 5 optimum properties.

Hardness of these alloys will vary depending naturally on the relativeproportions of mixtures A ahd B used. For the 90 A-lO B combination thehardness i's'about-72-76 Rockwell C; for the i i-20% B, it isabout'68-72; for the 70% A- 3078 B; it is about 60-64; andrer the 60% A-40% Bfit'i about 56-601 All values are of -hardnesjs Ro'ckwellc. l w r I7 The c'ombination that gave exceptionally good results 'vve're70%mixture A'- and 30% mixture =3"; mixture A contributing 65.8% byweight'of metal carbides, 4.2% by weight of cobalt and mixture 13'contributing 19.5% by weight of nickel plus beryllium combined, 75% byweight of manganese and' 3-% by'weight of copper to the final alloy. The-hardness of this pressed and s'inted alloy was about 60 -6 1 RockwellC, and it was extremely tough, shock and abrasion resistant.

C'oefiicients of thermal expansion of this groupof "alloys areconsiderably higher than 'for the ordinary sintered carbidecompositions. Values vary somewhat depending on composition. Forth'e*90%A l0% B combination the coefiicient is This pressure is,

acomeve approximately s s 1o+ pandror the 60% A-40% B it is 12-13 10 Forthe 70% A-30% B oombination it 1551.2 x 10- Values given are in; inchesp n z, pe 9 a e. a proxi a e av ra e va ues i9 1 e r e 09-609 seefih h rthe m l ex ans pn va ueslt 19? of this invention; is particularly welladapted be intere ndw t t ste lsha ordma ily s d nthe mi s an i. .wellzn s-t Th use aQ th al oy as a cr wiium te vnot; o l eliminates crackingand breakagedue toextr eine thermal strain but also eliminates aseparate brazing operation of the crown to the shank.

It is to be understood that where reference is made to various metalcarbides, that the respective saturated form of carbide is meant.

Having thus described my invention, what I claim is:

1. A pressed and sintered alloy of high strength and hardness, highthermal expansion and high abrasion and shock resistance comprising90-60% by weight of a first separately prepared mixture and 10-40% byweight of a second separately prepared mixture in which said firstmixture comprises 94% by weight of at least one metal carbide of thegroup consisting of tungsten, titanium, zirconium, vanadium, chromium,tantalum and molybdenum and 6 by weight of cobalt and said secondmixture comprises 65 by weight of nickel and beryllium combined, 25% byweight of manganese and 10% by weight of copper in which the berylliumis not less than 25% nor more than 3.0% of the total of said secondmixture.

2. A pressed and sintered alloy of high strength and hardness, highthermal expansion and high abrasion and shock resistance comprising90-60 by weight of a first separately prepared mixture and 10-40% byweight of a second separately prepared mixture in which said firstmixture comprises 94% by weight of tungsten carbide and 6% by weight ofcobalt and said second mixture comprises 65 by weight of nickel andberyllium combined, 25% by weight of manganese and 10% by weight ofcopper in which the beryllium is not less than .25% nor more than 3.0%of the total of said second mixture. I

3. A pressed and sintered alloy of high strength and hardness, highthermal expansion and high abrasion and shock resistance comprising90-60% by weight of a first separately prepared mixture and 10-40% byweight of a second separately prepared mixture in which said firstmixture comprises 79.9% by weight of tungsten carbide, 14.10% by weightof titanium carbide and 6% by weight of cobalt and said second mixturecomprises 65% by weight of nickel and beryllium combined, 25% by weightof maganese and 10% by weight of copper in which the beryllium is notless than 25% nor more than 3.0% of the total of said second mixture.

4. A pressed and sintered alloy of high strength and hardness, highthermal expansion and high abrasion and shock resistance comprising90-60% by weight of a first separately prepared mixture and 10-40% byweight of a second separately prepared mixture in which said firstmixture comprises 47.0% by weight of tungsten carbide, 32.9% by weightof molybdenum carbide, 14.1% by weight of titanium carbide and 6% byweight of cobalt and said second mixture comprises 65% by weight ofnickel and beryllium combined, 25% by weight of manganese and 10% byweight of copper in which the beryllium is not less than .25% nor morethan 3.0% of the total of said second mixture.

- 5.1.A- pressedi: and..- -.sintered..: alloy 1 of high strength andhardness, high thermal expansion and high abrasion and shock resistancecomprising -60% by weight of a first separately preparedzmixtureand.10-40% by weight of a second separately prepared mixture in whichsaid first mixture comprises 28.2%:by weight of tungsten carbide, 28.2by weight of molybdenum carbide, 18.8% by weight of titanium carbide,18.8% by weight of vanadium carbide and 6% by Weight of cobalt and saidsecond mixture comprises 65% by weight of nickel and beryllium combined,25% by weight of manganese and 19% by weight of copper in which theberyllium is not less than .25% nor more than 3.0% of the total of saidsecond mixture.

6. A pressed and sintered alloy of high strength and hardness, highthermal expansion and high abrasion and shock resistance consisting of70% by weight of a first separately prepared mixture and 30% by weightof a second separately prepared mixture in which said first mixturecomprises 94% by weight of tungsten carbide and 6% by weight of cobaltand said second mixture comprises 65 by weight of a nickel and berylliumalloy, 25% by weight of manganese and 10% by weight of copper in whichsaid nickel beryllium alloy contains beryllium in an amount not lessthan .25% nor more than 3.0% of the total of said second mixture.

7. A pressed and sintered alloy of high strength and hardness, highthermal expansion and high abrasion and shock resistance consisting of70% by weight of a first separately prepared mixture and 30% by weightof a second separately prepared mixture in which said first mixturecomprises 79.9% by weight of tungsten carbide, 14.10% by Weight oftitanium carbide and 6% by weight of cobalt and said second mixturecomprises 65% by weight of a nickel and beryllium alloy, 25% by weightof manganese and 10% by weight of copper in which said nickel berylliumalloy contains beryllium in an amount not less than 25% nor more than3.0% of the total of said second mixture.

8. A pressed and sintered alloy of high strength and hardness, highthermal expansion and high abrasion and shock resistance consisting of70% by weight of a first separately prepared mixture and 30% by weightof a second separately prepared mixture in which said first mixturecomprises 47 by weight of tungsten carbide, 32.9% by weight ofmolybdenum carbide, 14.10% by weight of titanium carbide and 6% ofcobalt and said second mixture comprises 65% by weight of a nickel andberyllium alloy, 25% by weight of manganese and 10% by weight of copperin which said nickel beryllium alloy contains beryllium in an amount notless than 25% nor more than 3.0% of the total of said second mixture.

9. A pressed and sintered alloy of high strength and hardness, highthermal expansion and high abrasion and shock resistance consisting of70% by weight of a first separately prepared mixture and 30% by weightof a second separately prepared mixture in which said first mixturecomprises 28.2% by weight of tungsten carbide, 28.2% by weight ofmolybdenum carbide, 18.8% by weight of titanium carbide, 18.8% by weightof vanadium carbide and 6% by weight of cobalt and said second mixturecomprises 65% by weight of a nickel and beryllium alloy, 25% by weightof manganese and 10% by weight of copper in which said nickel berylliumalloy con-

1. A PRESSED AND SINTERED ALLOY OF HIGH STRENGTH AND HARDNESS, HIGHTHERMAL EXPANSION AND HIGH ABRASION AND SHOCK RESISTANCE COMPRISING90-60% BY WEIGHT OF A FIRST SEPARATELY PREPARED MIXTURE AND 10-40% BYWEIGHT OF A SECOND SEPARATELY PREPARED MIXTURE IN WHICH SAID FIRSTMIXTURE COMPRISES 94% BY WEIGHT OF AT LEAST ONE METAL CARBIDE OF THEGROUP CONSISTING OF TUNGSTEN, TITANIUM, ZIRCONIUM, VANADIUM, CHROMIUM,TANTALUM AND MOLYBDENUM AND 6% BY WEIGHT OF COBALT AND SAID SECONDMIXTURE COMPRISES 65% BY WEIGHT OF NICKEL AND BERYLLIUM COMBINED, 25% BYWEIGHT OF MANGANESE AND 10% BY WEIGHT OF COPPER IN WHICH THE BERYLLIUMIS NOT LESS THAN .25% NOR MORE THAN 3.0% OF THE TOTAL OF SAID SECONDMIXTURE.